Abstract: An electrical limit switch (10) is provided and comprises a number of contact elements (30) each having a slot (32) with inner cutting edges (34) for penetrating the insulation of and containing a conducting element (48). The contact elements (30) are provided on a body which engages a base (56) wherein the base (56) receives a plurality of conducting elements (48). Upon engagement of the body and base (56), the conducting elements (48) are foced into respective slots (32) in the contact elements (30), thus providing a rapid electrical connection. The switching means of the limit switch (1) is provided by an actuating arrangement (14) including a plunger portion (16) and a roller (18), wherein the plunger(16) includes electrical contacts (36a, 36b) which are moveable with the plunger. Each contact (36a, 36b) provides an electrical connection between two of the contact elements (30) when the plunger (16) is in the appropriate position.

Abstract: A liquid level sensor comprises a light source in the form of a semiconductor device, a light sensor also in the form of a semiconductor device, and an optical element arranged to transmit light from the light source and to receive reflected light and transmit it to the light sensor, the liquid level sensor further comprising a carrier having gas-filled cavities means in which the light source and the light source and the light sensor are respectively mounted, the cavities being separated by barrier means to prevent scattered light reaching the light sensor from the light source. The mounting of the light source and light sensor in gas-filled cavities extends significantly the operating temperature range of the liquid level sensor.